Hand-book of physiology / by W. Morrant Baker and Vincent Dormer Harris.

  • William Morrant Baker
Date:
1892
Catalogue details

Licence: Public Domain Mark

Credit: Hand-book of physiology / by W. Morrant Baker and Vincent Dormer Harris. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

    142/914 (page 120)
    Non-nitrogenous organic bodies consist of (a) Oils and Fats, which are for the most part mixtures of palmitiMj C51H90O6, stearin C57H110O6, and olein C57H104O6, in different proportions. They are formed by the union of fatty acid radicals with the triatomic alcohol, Glycerin C3H5(OH)3, and are etherial salts of that alcohol. The radicals are C18H350, C16H310, and C18H330, respectively. Human fat consists of a mixture of palmitin, stearin, and olein, of which the two former contribute three-quarters of the whole. Olein is the only liquid constituent. Fats are insoluble in water and in cold alcohol; soluble in hot alcohol, ether, and chloroform. Colourless and tasteless ; easily decomposed or saponified by alkalies or super-heated steam into glycerin and the fatty acids. And (b) Carbo-hydrates, which are bodies composed of six or twelve atoms of carbon with hydrogen and oxygen, the two latter elements being in the proportion to form water. There are three main classes of carbohydrates. Amyloses, C6H10O5, comprising Starch, Dextrin, Glycogen, &c. Saccharoses, C12H2201]L, Saccharose, or Cane sugar, Lactose, Maltose, &c. Glucoses, C6H1206, Dextrose or Grape sugar, Leevulose or Fruit-sugar, Inosite, &c. Of these the most important are : Starch (C6H10O5), which is contained in nearly all plants, and in many seeds, roots, stems, and some fruits. It is a soft white powder composed of granules having an organised struc- ture, consisting of granulose (soluble in water) contained in a coat of cellulose (insoluble in water); the shape and size of the granules varying according to the source whence the starch has been obtained. It is insoluble in cold water, in alcohol, and in ether; it is soluble after boiling for some time, and may be filtered, in consequence of the swelling up of the granulose, which bursts the cellulose coat, and becoming free, is entirely dissolved in water. This solution is a solution of soluble starch or amydin. It gives a blue coloration with iodine, which disappears on heating and returns on cooling. It is converted into dextrine and grape-sugar by diastase or by boiling with dilute acids. Glycogen, which is contained in the liver, is also present to a considerable extent in the muscles of very young animals, in the placenta, in colourless corpuscles, and in embryonic tissues. It is freely soluble in water, and its solution looks opalescent; it gives a port-wine coloration with iodine, which disappears on heating and returns on cooling. It is precipitated by basic lead acetate and insoluble in absolute alcohol and in ether. It exists in the